DebugFS : more file/directory creation error handling
Mathieu Desnoyers [Fri, 24 Nov 2006 18:50:09 +0000 (13:50 -0500)]
Correct dentry count to handle creation errors.

This patch puts a dput at the file creation instead of the file removal :
lookup_one_len already returns a dentry with reference count of 1. Then,
the dget() in simple_mknod increments it when the dentry is associated
with a file. In a scenario where simple_create or simple_mkdir returns
an error, this would lead to an unwanted increment of the reference
counter, therefore making file removal impossible.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

fs/debugfs/inode.c

index d6c5fb5..554f4a9 100644 (file)
@@ -162,6 +162,7 @@ static int debugfs_create_by_name(const char *name, mode_t mode,
                        error = debugfs_mkdir(parent->d_inode, *dentry, mode);
                else 
                        error = debugfs_create(parent->d_inode, *dentry, mode);
+               dput(*dentry);
        } else
                error = PTR_ERR(*dentry);
        mutex_unlock(&parent->d_inode->i_mutex);
@@ -273,6 +274,7 @@ EXPORT_SYMBOL_GPL(debugfs_create_dir);
 void debugfs_remove(struct dentry *dentry)
 {
        struct dentry *parent;
+       int ret = 0;
        
        if (!dentry)
                return;
@@ -284,11 +286,15 @@ void debugfs_remove(struct dentry *dentry)
        mutex_lock(&parent->d_inode->i_mutex);
        if (debugfs_positive(dentry)) {
                if (dentry->d_inode) {
-                       if (S_ISDIR(dentry->d_inode->i_mode))
-                               simple_rmdir(parent->d_inode, dentry);
-                       else
+                       if (S_ISDIR(dentry->d_inode->i_mode)) {
+                               ret = simple_rmdir(parent->d_inode, dentry);
+                               if (ret)
+                                       printk(KERN_ERR
+                                               "DebugFS rmdir on %s failed : "
+                                               "directory not empty.\n",
+                                               dentry->d_name.name);
+                       } else
                                simple_unlink(parent->d_inode, dentry);
-               dput(dentry);
                }
        }
        mutex_unlock(&parent->d_inode->i_mutex);